Dishwashing machine



Nov. 6, 1951 Filed Sept. 19, 1947 O.D.KUENEMAN DISHWASHING MACHINE 2 SHEETSSHEET l Nov. 6, 1951 o. D. KUENEM-AN 27,573,794

DISK-{WASHING MACHINE Filed sept. 19, 1947 2 SHEETS-SHEET 2 OSWALD D. KUE/VEMAN atented Nov. 6, 1951 2.513.794 s nrsnwasmno MACHINE Oswald D. Kuencman, Berkeley, Calif., assignor to Kaiser Metal Products, Inc., a corporation of California Application September 19, 1947, Serial No. 774.953

4 Claims. (Cl. 134-138) This invention relates to improvements in dishwashing machines, and more particularly to dishwashing machines employing a hydraulic lift device for raising and lowering a rotatable dish container within the dishwasher tub.

In the constructions of the prior art, hydraulic cylinders have heretofore been employed for raising and lowerin therotatable basket or dishsupporting member to facilitate the loading and unloading operation and the drying of dishes in hydraulic dishwashing machines of the type wherein the cleansing action and rotational movement of the basket is effected solely or predominantl by liquid under pressure. Such prior constructions have applied fluid pressure to the both sides of the piston, with the result that dirt and other foreign matter may inadvertently be drawn into the cylinder so as to necessitate frequent servicin and repair of the hydraulic lift device.

It is the principal object of the present invention to provide an improved hydraulic system for a dishwashing machine wherein a single source of liquid under pressure is adapted to impart a cleansing action and rotational movement to a dish-containing basket and to the contents thereof solely by liquid under pressure, and to actuate a hydraulic cylinder and piston adapted to vertically raise and lower the dish container by applyin fluid pressure to not more than one side of the piston during intermittent reciprocating movement of the actuating plunger.

It is a further object of the instant invention to provide a dishwashing machine wherein a single source of liquid under pressure is adapted to impart a cleansing action and rotational drying movement to a dish-containing basket and to the contents thereof, and by admitting uncontaminated liquid from said single source into a hydraulic cylinder in such a manner as exert fluid pressure on only one side of the piston contained therein to move the piston and the basket in opposition to a resilient means, and by periodically discharging to a drain the portion of the said liquid admitted to the cylinder which seeps past the piston during the reciprocation thereof.

Such objects are accomplished by providing in a dishwashing machine a rotatable dish-containing basket, a tub having a drain in the bottom portion thereof, a hydraulic cylinder having a piston therein, a shaft adapted to be reciprocated by the piston and adapted at one end to rotatably support the basket within the tub, a single source of liquid under pressure adapted to move said piston and to discharge spray within the tub,

means for admitting a portion of said liquid to said cylinder for exerting fluid pressure on not more than one side of said piston, and means for discharging to a drain that portion of the fluid within the cylinder which seep past the piston during the reciprocation thereof.

Figure 1 is a front elevation view of my improved dishwashin machine in which the dishcontaining basket is shown in full lines in its depressed position, and in dotted lines in its elevated position. v

Figure 2 is a vertical mid-section of th hydraulic lift device on an enlarged scale.

Referring now to the drawings, I have shown a dishwashing tub l0 having cylindrical sides II and a bottom portion I2. Extending through the bottom of the tub is a vertically disposed overflow pipe I3 having an upper portion I4 and a lower portion l5 adapted to be slidably supported within the upper extremity of an external drain pipe l6 which is secured by an annular flange IT to the bottom of the tub and in liquid-tight engagement therewith. Intermediate the upper and lower portions of the overflow pipe I3 is an annular ring I8 adapted to effect a liquid-tight seal with the bottom of the tub i2. The annular ring I8 is positioned transversely of the overflow pipe l3 so that the upper portion M will establish a predetermined liquid level in the tub Ill whenever the overflow pipe I3 is in its normal or lowermost position established by contact between the annular ring as and the bottom of the tub l2. The

lower portion l5 of the overflow pipe preferably has a plurality of longitudinally extending apertures l9 formed in the surface thereof adapted to facilitate the flow of liquid from the bottom of the tub and into the drain pipe l5 whenever the overflow pipe I3 is in the raised position and the annular ring I8 is not in liquid-tight engagement with the bottom of the tub l2.

Rotatably mounted within the upper extremity of the drain pipe I6 and transversely of the axis thereof is a pin 20 carrying a cam 2| adapted to contact the lower portion l5 of the overflow pipe l3 for the vertical reciprocation thereof. A drainage control 9 is operably connected through the arm 22, rod 23 and lever 24 in such a manner as to impart angular displacement to the pin 20 within predetermined limits and for bringing the cam 2| into contact with the lower portion l5 of the overflow pipe.

The .external drain pipe l6 preferably but not necessarily has a T-portion 25 communicating the pipe "5 with a conduit 26 and an elbow 21, which is adapted to vertically support a standpipe 28 within the tub In by the upper portion M of the overflow pipe. If desired, the standpipe may be connected to a drainage pipe which is independent of the pipe IE, but the same external drainage connection I6 is preferably employed for both the overflow pipe l3 and the standpipe 23.

A permeable basket or dish-container 38 is vertically disposed within the tub l and preferably has a perforated cylindrical compartment 3|, adapted to hold tableware and other small articles, mounted inside the basket with its axis concentric with the axis thereof. The basket 38 is rotatably supported by the bottom portion l2 of the tub, preferably with its axis of rotation coinciding with the vertical axis of the tub. In vertical alignment with the axis of the basket 30, but disposed on the opposite side of the tub bottom from the basket, is a hydraulic cylinder 32 having a lower chamber 33, an upper chamber 34, and a piston 35 therebetween. The upper end of the cylinder is preferably secured to the bottom of the tub I2 by a suitable attaching means. such as the tubular connection 35, and the piston 35 is operably connected to the basket 30 by a shaft or plunger 31. A suitable anti-friction bearing member 38 rotatably supports basket 30 on the upper extremity of the shaft 31, and bracing members 38 are preferably employed to provide additional structural support for the hasket 30.

A shut-off valve 40 communicates both the conduit 4| and the conduit 42 with a hot water system or other single source of fluid under pressure, not shown. Preferably this pressurized fluid is hot water, but under some circumstances cold water or other cleansing fluids can be employed without departing from the scope of my invention.

Conduit 4| communicates the source of fluid under pressure with a two-way lift control valve 43, which in turn is adapted to permit the pressurized fluid to flow through the delivery conduit 44 and into the manifold pipe 45. Preferably,

but not necessarily, a siphon breaker of conventional design, not shown, is inserted in the delivery conduit 44 to prevent improper fluid flow in the event of unusual pressure conditions in the drainage system. To the manifold pipe 45 are fastened a plurality of vertically disposed unions 46 connected to the bottom of the tub |2 in a leakproof manner and each having threaded openings extending through the bottom of the tub. Threadedly engaged with the top portion of each of the unions 46 is a fluid discharge jet 41 adapted to discharge a spray mixture into the tub III in such a manner as to impart a rotational movement to the basket 38 and a cleansing action to the contents thereof. A suitable metallic or non-metallic cover, not shown, is preferably provided to prevent the escape of spray from the tub |0 whenever the discharge jets 41 are in operation.

The conduit 42 communicates the source of fluid under pressure with a three-way lift control valve 48 which in turn is adapted to permit a portion of the fluid from the pressurized source to flow through a conduit 49 and into the lower chamber 33 and to force the piston to its fully elevated position so as to raise the dish-containing basket 30 vertically out of the tub "I in the v 4 manner indicated in Figure 1. Upon manually returning the valve 48 to its normal position, substantially all of the fluid entrained in the lower chamber 33 during the upward movement of the piston 35 is allowed to flow through conduit 48, valve 48, discharge conduit 50, and into the standpipe 25.

Upper chamber 34 of the cylinder 32 is normally not subjected to the action of fluid under pressure, but serves as an accumulation chamber for such leakage fluid from the lower chamber 33 as may result from wear of the contacting surfaces of the piston 35 and the cylinder 32. A drainage conduit 5| discharges such leakage fluid into the standpipe 28 upon upward movement of the piston 35.

Preferably, though not necessarily, a check valve may be installed in the conduit 42. A second siphon breaker of known design, not shown, is also preferably inserted in the conduit 42 to protect the hydraulic cylinder 32 from possible damage in the event of unusual pressure fluctuations in the hydraulic system.

Referring now to Figure 2, there is shown a tubular connection 36 adapted to secure the hydraulic cylinder 32 to the bottom portion I! of the tub in a leakproof manner. The cylinder 32 includes an external tube 52 having a threaded upper portion and the tubular connection 35 having a threaded lower portion 53 extending through the tub bottom |2 for engagement with the upper portion of tube 52. The lower end of the cylinder 33 is closed by means of a cap 54, there being a space 55 provided between the closed end of the cap 54 and the end of the cylinder.

The connection 36 is provided with an annular flange 55 which overlies the adjacent surrounding portion of the bottom of the tub ID, the said flange assuming a substantial portion of the weight of the lift together with that of the basket 38 and the dishes supported thereby.

In order to make a leakproof joint between the flange 56 and bottom portion 2 of the tub, I provide a gasket 51 which is securely held in place by the annularly flanged lock nut 58.

concentrically supported slidably within the tube 52 is the hollow shaft or plunger 31. On the lower end of the shaft 31 is fastened a dual packing gland 58 whereby the annular space 60 between the tube 52 and the shaft 31 at that point is closed.

At the upper end of the shaft 31 I provide a second packing gland 8|. This gland is formed in the connection 36 and provides a seal for preventing the fluid in the tub from entering the space 60.

Into the upper end of the plunger is screwed a plug 62, said plug being provided with a hole 63 axially tapped into its lower end and having the mouth of the hole conically tapped. Into the hole 53 is screwed a screw 64 having fastened to its head one end of a. spirally coiled spring 55. The other end of the spring is fastened to an anchor pin 56 which underlies the lower end of the cylinder.

When the three-way lift control valve 48 is manually operated so as to place the conduit 42 in communication with the conduit 49, fluid from the single source under pressure flows through the valve 48, the conduit 49, and into the lower chamber 33 so as to exert fluid pressure against the piston 35, thereby elevating the piston and the shaft 31 against the opposition of thecoiled spring 65. During the elevation of the shaft 31, the antifriction bearing member 38 permits any angular momentum of the dish container 3|! and its contents to continue the rotational movement of the container for a substantial period of time after the container has been elevated to its fully raised position so as to dry the contents thereof by inducing the movement of air around articles therein having surfaces exposed to contact with the atmosphere. This rotational movement continues urin the elevation of the dish container and for a substantial period after the container has reached the fully elevated position.

When it is desired to lower the basket 30 into the tub II], the three-way valve is again manually actuated to place the fluid entrapped in the lower chamber 33 in communication with the standpipe 28 through the conduit 49, valve 48, and the fluid discharge conduit 50. The weight of the basket 30 and its contents assists the coiled spring 65 in inducing the flow of the entrapped fluid out of the lower chamber 33 and into the standpipe 28 whenever the valve 48 is actuated to place the conduit 49 into communication with the fluid discharge conduit 50.

By maintaining a predetermined liquid level in the bottom of the tub l during the discharge of liquid under pressure through the unions 46, I am able to continuously recirculate the detergent-containing liquid in the bottom of the tub through partially submerged aspirator passageways in the discharge jets 4! in such a manner as to form a spray mixture with the liquid flowing into the jets 41 through the unions 46. This predetermined liquid level is maintained by the upper portion 14 of the overflow pipe l3 whenever the cam 2| is out of engagement with the lower portion l5 of the overflow pipe so that annular ring 18 is in sealing engagement with the bottom portion l2 of the tub.

When the dishwasher is not in use and it is desired to completely drain the liquid from the bottom of the tub ID, the drain control 9 is manually turned to angularly displace the lever 22, reciprocate the rod 24, and to angularly rotate the arm 24 and pin 20 so that the cam 2| is brought into engagement with the lower portion l5 to elevate the overflow pipe to the raised position indicated in Figure 1. The upward movement of the overflow pipe IS with respect to the drain pipe l6 breaks the seal between the annular ring l8 and the bottom portion H of the tub so as to allow the liquid in the bottom of the tub to flow through the apertures l9 and into the external drain pipe l6.

From the above description, it will be evident that I have produced an improved dishwashing machine wherein a single source of fluid under pressure is employed to actuate the hydraulic lift device and to rotate the dish container solely by liquid under pressure. It is further evident that I have provided a hydraulic lift device for a dishwasher wherein no scavaging action of the cylinder is required and into which no contaminating fluid can be drawn so as to cause excessive wear in the event the lift is inadvertently operated during abnormal pressure conditions in the actuating fluid and in the associated drainage system. I have also made provision for draining away from the lift device any leakage fluid which may result from normal wear of the contacting surfaces between the hydraulic cylinder and lift actuating piston.

Although only one form of the invention has been described in detail, it will be apparent to those skilled in the art that various modifications may be made without departing from the scope of the appended claims.

What is claimed is:

1. In a dishwashing machine of the type wherein a single source of liquid under pressure is adapted to rotate and vertically reciprocate a dish-containing basket, the combination comprising a basket. a tub, a first drainage means in the bottom of the tub adapted to maintain a predetermined liquid level therein, a second drainage means adapted to receive discharge liquid at a level above said predetermined liquid level in said tub, a hydraulic cylinder mounted on the bottom of said tub with its upper extremity in fluid-tight engagement therewith, a shaft rotatably connected at one end to said basket'and extending into said cylinder and having a piston at its other end, means for spraying liquid upon the basket and its contents, a single source for supplying liquid under pressure to said spraying means and to said cylinder, control means for alternately causing liquid to flow from said single source through a piping system to the one end of said cylinder to thereby actuate said piston and said shaft to raise said basket and then for causing discharge of said liquid from said cylinder only to said second drainage means through at least a portion of the said piping system through which the liquid enters said cylinder to thereby lower said piston and said basket and thus exert fluid pressure on not more than one side of the said piston, means including said portion of said piping system for directly connecting the one end of said cylinder to said second mentioned drainage means, and by-passing the other end of said cylinder and a conduit separate and apart from said last mentioned means for directly connecting said other end of said cylinder to said second mentioned drainage means and for discharging into said second drainage means that portion of the liquid within the said cylinder which seeps past said piston during the reciprocation thereof.

2. In a dishwashing machine of the type wherein a single source of liquid under pressure is adapted to rotate and vertically reciprocate a dish-containing basket, the combination comprising a basket, a tub, a drainage control means, a lower drainage connection operably connected to said control means for selectively maintaining a predetermined liquid level in said tub and for completely draining said tub, an upper drainage means adapted to receive discharge liquid at a level above said predetermined liquid level, a hydraulic cylinder vertically mounted on the bot tom of said tub with its upper extremity in fluidtight engagement therewith, a shaft connected at one end to said rotatable basket and extending into said cylinder and having apiston at its other end, means for spraying liquid upon the basket and its contents, a single source for supplying liquid under pressure to said spraying means and to said cylinder, control means for alternately causing liquid to flow from said single source through a piping system to the one end of said cylinder to thereby actuate said piston and said shaft to raise said basket and then for causing discharge of said liquid from said cylinder and into said upper drainage connection through at least a portion of the said piping system through which the liquid enters said cylinder to thereby lower said piston and said basket and thus exert fluid pressure on not more than one side of said piston, means including said portion of said piping system for directly connecting the one-end of said cylinder to said upper drainage means and by-passing the other end of said cylinder and a conduit separate and apart from said last mentioned means for directly connecting said other end of said cylinder to said upper drainage means and for discharging into said upper drainage means that portion of the liquid within the said cylinder which seeps past said piston during the reciprocation thereof.

3. In a dishwashing machine including a tub having a drainage means in the bottom portion thereof adapted to maintain a predetermined liquid level in the tub, a dish-containing basket, a hydraulic cylinder mounted on the bottom of said tub, a vertical shaft rotatably connected at its upper end to said basket and extending into said cylinder and having a piston at its other end, and a means for spraying liquid upon the basket and its contents, the improvement which comprises a single source adapted to supply liquid under pressure to said spraying means and to said cylinder, control means for alternately causing liquid to flow from said single source through said piping system to the one end of said cylinder to thereby actuate said piston and said shaft to raise said basket and then for causing discharge of liquid from the one end of said cylinder to said drainage means through a portion of the said piping system through which the liquid enters said cylinder to thereby lower said piston and said basket and thus exert fluid pressure on only one side of said piston means including said portion of said piping system for directly connecting the one end of said cylinder to said drainage means while by-passing the other end of said cylinder and a conduit separate and apart from said last mentioned means for directly connecting said other end of said cylinder to said drainage means and for discharging into said drainage means that portion of the liquid within the said cylinder which seeps past said piston during the reciprocation thereof.

4. In a dishwashing machine including a tub having a drainage means in the bottom portion thereof adapted to maintain a predetermined liquid level in the tub, a dish-containing basket, a hydraulic cylinder mounted on the bottom of said tub, a vertical shaft rotatably connected at its upper end to said basket and extending into said cylinder and having a piston at its other end, and a means for spraying liquid upon the basket and its contents, the improvement which comprises a single source for supplying liquid under pressure to said spraying means and to said cylinder, control means for alternately causing liquid to flow from said single source through a piping system to the one end of said cylinder to thereby actuate said piston and said shaft to raise said basket and then causing discharge of liquid from said cylinder to said drainage means through at least a portion of said piping system to thereby lower said piston and said basket and thus exert fluid pressure on only one side of said piston, resilient means for returning the said piston moved by said liquid under pressure and tending to force fluid out of said cylinder and into said means including said portion of said piping system for directly connecting the one end of said cylinder to said drainage means while bypassing the other end of said cylinder and a conduit separate and apart from said last mentioned means for directly connecting said other end of said cylinder to said drainage means and for discharging to said drain that portion of the liquid within the said cylinder which seeps past said piston during the reciprocation thereof.

OSWALD D. KUENEMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,315,572 Wilson Apr. 6, 1943 2,387,299 Ronci Oct. 23, 1945 2,512,452 Wilson June 20, 1950 

